


A Very Trying Set of Circumstances

by LuxrayOnAO3



Category: Fire Emblem: Kakusei | Fire Emblem: Awakening
Genre: Anal Sex, F/F, F/M, Sibling Incest, Threesome - F/F/M
Language: English
Status: Completed
Published: 2019-06-19
Updated: 2019-06-21
Packaged: 2020-05-14 23:20:13
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 6,668
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19283272
Author URL: https://archiveofourown.org/users/LuxrayOnAO3/pseuds/LuxrayOnAO3
Summary: Lucina likes to have her sister join them. But she’d never admit it.





	1. Chapter 1

Their first time should never have happened. 

“Robin, this is reprehensible,” Lucina had hissed, the sheet drawn up against her naked chest. “Cynthia is my sister! In what possible way did you think bringing her to our bedroom was appropriate?” 

The tactician’s face was a picture of dejection, the white-haired man taking a breath to compose himself, before beginning what he considered a measured apology. “I’m sorry, Luce,” he began; “it’s just… uhm… stuff happened, today. So I’m sorry to do it now, when you’re in bed, but we both agreed that it shouldn’t wait, probably.” Robin looked uncertainly at Cynthia. Lucina felt her heart beginning to drop in her chest. 

Cynthia was running a hand over her head, fingers interspersed with the blue hair she shared with her sister. “I… I kissed him, okay?” she blurted, immediately looking sidelong at the wall, folding her arms quickly. “I know I shouldn’t have. I know I’m a horrible person for doing it. But Robin and I agreed… we should come here and tell you that I did…” Cynthia was biting back tears now, her usual brash and enthusiastic demeanour warped into one of sorrow. “LucyI’msosorryIjustforgotmyselfand--” 

Lucina recoiled slightly as if struck, and Robin interjected quickly -- “Please, Luce, it didn’t go any further than that. We just wanted to be honest, okay?” 

The blue-haired princess in the sheets looked around for something to cover herself with, nothing proving at hand. She blinked slowly. “Could you find me something to cover myself with,” she asked Robin, demurely. Robin got up and strode to the wardrobe, pulling out one of his undershirts, passing it to Lucina gingerly. Her long fingers deftly opened it and held it up over her head, the fabric falling around her chest. Lucina swung her legs out of the bed, the long shirt falling around her waist and over her hips to establish a semblance of modesty. The hem settled on her lean, pale thighs. 

Lucina walked slowly over to where Cynthia was sobbing at the doorway. She reached out a hand to her sister’s cheek, the flesh under her palm wet with tears. “Shhh,” she urged, wiping away the dampness, “it’s alright, Cynthia.” 

“Hardly,” Cynthia cried, the words catching like nails in the back of her throat. “I’m sorry, Lucy.”

“It’s fine,” Lucina said, trying to look reassuring. “I mean, you came here and told me, right? I… respect and appreciate that; I’m not exactly pleased with what you two have supposedly done, but I’m glad you were honest with me. Frankly, compared to some of the stuff we had to deal with in the Future-Past, this is nothing. So if you want to draw a line under it, I’d be happy to do so as well. How does that sound?” 

Cynthia took a deep breath, the tears causing it to be sniffly and immodest. “Lucy, I’m so sorry, but I had to. It’s just… your husband is so… nice, and kind, and he’s my friend, and so are you, so I just forgot myself, but I’m so scared now that everything will be ruined and you’ll hate me--”

“Shhh,” Lucina urged, putting her hands flat on her younger sister’s shoulders. “It doesn’t have to be a big deal, okay? I must confess I feel quite jealous that you would do such a thing, but--” 

Lucina’s words were cut off as Cynthia had put her own hands around her sister’s cheeks, pulling her sister into a sudden kiss as well. Cynthia’s face was warm, if tracked with tears, but her lips were hot and soft. Lucina let out a muffled noise of surprise as her sister’s mouth clamped over hers, her sister’s wet lips burning hers for a moment before she pushed away--

“Cy-Cynthia!”

“Now it’s even, okay?” Cynthia blinked, a weak, tear-laden smile on her face. She put three fingertips to her lip, touching the place where they had kissed. “Sorry, Lucy. I didn’t plan that.”

Lucina was struggling for composure, her own hand touching her lips, as if to confirm what had happened. “I… ah, clearly not…”

“You know I love you, Luce,” Robin was murmuring, his arms around her now, his chest pressing into her back.

The former Exalt shivered. “Yes, and I you, even when you bring my sister to our bedroom with tales about kissing. But I forgive the two of you, anyway. We can let that be the end of it.”

Robin had the decency to blush at least. “I didn’t mean it to go quite like this. But.. what if we… I mean, if I suggested something… well, less orthodox…”

Lucina put her arms around his where they wrapped her body, their skin settling against each other. She nodded, barely.

Robin pressed his lips directly into Lucina’s ear, her blue hair tickling his face as he whispered something despicable to her.

“What if we put this drama aside for the night and have your sister join us in bed for a more comprehensive apology,” he murmured.

Cynthia’s eyes widened; Lucina’s jaw dropped.

The pegasus knight’s face was crimson, the suggestion of just such an act causing her current panicked look. “Robin!”

Lucina regained her composure slightly, shivering in Robin’s arms. They were warm, like her mouth, where her sister had kissed her. Her eyes ran over Cynthia’s face; her sister had a curious look, before nodding very slightly. “That is perhaps the most scandalous thing I’ve ever been propositioned with, and we know Inigo, for heaven’s sake…”

Her sister laughed, the sound a break in the tense atmosphere. “You always look at the floor when you don’t want to give away your emotions,” Cynthia said, an uncertain smile forming on her face. “This is totally bizarre, and _definitely_ unheroic. But for you, Lucy, I’ll make an exception.”

Then Cynthia stepped closer, eliminating the distance between the sisters, and kissed her again.

Lucina’s lips were trembling tentatively as they again met her sister’s, but when their kiss began soft and warm, they slowly quieted. Lucina was used to kissing Robin, who took the lead oftentimes, but in this case it was Cynthia who was the submissive one, allowing her sister to press liquidly into their embrace.

The girls held it for a few seconds, and then Lucina pulled back slowly, seeing Cynthia’s eyes glazed with a surprising desire. One matched by hers.

“Ah, Lucy, what the….” Cynthia said slowly, her heart pounding. “Mmf… again…”

The pegasus knight moaned softly as their kiss began again, more impassioned this time, and Lucina’s shirt-clad body pressed into her, their bodies meeting before Lucina pushed her sister backwards, the girl stumbling until the pair met the wall. The princess pushed her tongue into her sister’s mouth. Cynthia's mouth tasted like mint.  _And Robin._ She pressed forward, clothes be damned, sister be damned, all she could think about was the softness of the girl's mouth and the pleasurable taste of her--

“Just so you know, I didn’t plan this,” Robin said dryly, standing back and watching appreciatively. “I didn’t expect Cynthia to kiss _you_. But you seem to have risen to it...”

Robin could feel himself rising to the occasion. He began to wonder who it would be politer to move on first. It would have to wait, though; Cynthia’s arms were pinned against the wall by her sister, who was crimson-faced as she pushed her tongue into the back of the girl’s throat.

“Hah,” Cynthia breathed, pulling her head back to breathe, their lips connected by a silvery strand. “This is so weird, but I like it, Lucy…”

“This is wicked,” Lucina confessed, the heat of desire in her face burning like shame. “It’s so different kissing a woman, let alone my sister. But I like it, too.” The princess delivered a quick, gentler kiss to Cynthia’s lips before she pulled away, smiling embarrassed. “Robin,” she called back, breathing heavily, “come take my sister’s clothes off.”

Her husband needed little more instruction.

 

* * *

 

Their second time had been a week after the first.

“Don’t bother to deny it, Lucina,” Robin had said, his quirked eyebrow betraying his amusement from the doorway. “What point is there in being stoic, to deny something you want to do anyway?”

“Yeah, sheesh, don’t be like that, sis,” Cynthia smiled, crossing the space from the door to the bed, the bedsheets jumping as she plonked herself down, carefree. She pouted in front of her sister. “Such a meanie, sis,” Cynthia teased; she attempted to flutter her eyelids coquettishly, elegantly -- Lucina rather thought she looked ridiculous. “The Hero of Justice has arrived! To save you from… yourself! So quit being frumpy and say yes...”

This was enough to break Lucina’s mask, and the wry smile she had been successfully suppressing up until now edged onto the corner of her mouth. “Your heroics do amuse me, sister. I suppose I am going to be rescued by our romantic tryst?”

Cynthia grinned, beckoning Robin over. “Yep. Now quit stalling when we could be making out with each other already.” Cynthia kissed her sister, Lucina smiling as their lips met again,  tossing her hair back and undoing the fasteners on her tunic.  


 

* * *

 

The third time, no further words were needed.

The three of them moved on each other quickly, that _need_ at the sight of each other and the bedroom becoming linked. As her underwear was being pulled off Cynthia wondered what the other Shepherds would think about this; then she realised she didn’t much care.

Lucina let out a deep noise of pleasure, cogent thought long-since driven out. Robin moved inside her, his hand on her back between the shoulders driving her chest into the bed, even as her knees were bent under her, her hips slapping against his pelvis. Competing with the hot, full, _pleasurable_ feeling of their coupling was the girl underneath her; Cynthia’s tongue was eagerly seeking the back of her sister’s throat, the younger girl’s wicked fingers playing with Lucina’s breasts, her nipples toyed with in that infuriating way that Cynthia somehow innately knew and was so good at. “Nnnnf,” Lucina moaned, as Cynthia elicited this wicked pleasure from her, Robin’s cock and hand at her core nearly driving her eyes into the top of her head.  Robin let out a grunt of pleasure, and moved his hips forward; Lucina groaned as she was pressed into her sister’s more soft and voluptuous chest, the younger girl’s assets rubbing against her deliciously as Robin dictated her motion entirely. Cynthia broke off their kiss, gasping for air and grinning as Lucina squirmed over her, pulling the older girl’s face into her neck as Cynthia’s buxom chest rubbed deliciously against her sister’s flat one.

“Ah, Lucy, this is hot,” Cynthia whispered fervently, kissing her sister’s neck as Lucina reciprocated, their lips urgently moving over each other, open-mouthed and hot. Lucina shuddered as Cynthia’s soft tongue lapped at her neck, hot and wet and rough in texture.

“You, ah, you say that every time, ahh,” Lucina moaned, the sister under her working her mouth in tandem with Robin’s cock to stimulate her wetly at both ends. It was an effective combination, and Lucina could feel her limbs weakening and her core growing more hot.

“Gods, it’s true, though,” Cynthia whimpered, pulling Lucina back into kissing. “Mmmph-- watching you get fucked is so fucking _hot._ ” She looked at Robin, the tactician’s face flushed as he took pleasure in his wife and the sight in front of him. “I hope you’re going to cum inside my sister,” Cynthia teased, Lucina’s mouth against her neck making all manner of low pants and moans. “Just make sure you’ve got enough for me, after _your wife_.”

She winked at Robin, who winked back. “I’ve got more than just one in me,” he offered, face flushed. Cynthia grinned, and kissed her sister’s face. “When he comes inside you, I’ll clean you up,” she urged, the desire in her face to do so evident. “So come for us, okay? Come as messily as you like, Lucy. _”_

Lucina moaned, her sister’s pillow-talk heightening her pleasure as she drooled into Cynthia’s neck. “A-Ah, Cynthia, gods… move, get up the bed,” she urged, panting. “I can kiss you, ahhh, kiss you somewhere more effective.”

Her sister scrambled up the bed from under her. Lucina took her sister’s hips in her hands, the girl’s bearing wider than hers, becoming more familiar by nights. She pulled the girl into position, before her mouth clamped hungrily on Cynthia’s wet cunt, the girl shuddering as she felt Lucy’s wet tongue lap around her most sensitive part. “Ahhhh,” Cynthia moaned, her face hot, her core hotter under her sister’s tongue, Lucina lapping over the knight’s core with her wet tongue eagerly. “H-hah, Lucy-yy,” Cynthia panted, the warmth of her older sister’s mouth moving blissfully firm against her core. “Oh, sis, I’m not gonna-- I won’t-- I won’t last long like this--”

As Lucina began delivering a different kind of kiss to her sister, the princess hummed throatily, the vibration through her mouth transferring to Cynthia’s core, the pegasus-rider moaning from the knock-on effect. “I’m close too, Cynthia,” Lucina admitted between motions, as demurely as being the cause of one’s sister’s pleasure allowed, that same sister’s hands deep within her long hair pushing her more firmly into her needy core. “It’s trite to come together, but let’s try,” Lucina moaned, resuming her congress with Cynthia as Robin pushed deeper inside her, the tactician nearing his own end.

“Ah, I’m close too, girls,” he moaned, pushing sweat-slicked hair off his forehead, his cock pulsing hard inside his wife, so close to reaching his own climax. Lucina felt him move more erratically inside her, his thrusting becoming less regular as the pleasure of her overwhelmed him.

“You better come deep inside her, Robin,” Cynthia moaned, Lucina’s mouth too busy to speak between heavy breaths and making her sister come too. She gasped as she felt her own climax beginning to build; her sister’s hot tongue pushing over her core, Lucina’s slender fingers delving insistently inside her now too, filling Cynthia and giving her something firmer to come around. “Gods, Lucy, I’m gonnna come so hard, how are you so gooood at this,” she cried, her eyes watery as the pleasure overwhelmed her. “Lucyyy, I’m, I’m gonna--”

And then Cynthia did come, climax sparking in her, chased out wetly by the movement of her sister’s tongue; and the girl moaned as she pressed Lucina’s face between her trembling  thighs, the princess moaning lewdly as she licked-and-fingered her sister through a shaky and long orgasm, Cynthia’s tongue lolling as her body convulsed and pleasure ran through her at Lucina’s doing.

Robin groaned, seeing Cynthia coming so hard and long enough to tip him over the edge, too. “Luce-- Cyn-- I’m coming--” he cried, and he let out a guttural moan as his cock exploded wetly inside Lucina, strand and strand of his seed hitting her insides like a torrent. His hips pressed eagerly against his wife’s firmly, his fingertips digging into Lucina’s skin in earnest, the manifestation of his pleasure hitting Lucina’s insides.

And as she felt Robin’s cum hit her insides, the warmth of his erection having radiated heat and pleasure into her for the last dozen minutes, Lucina came too; rather than pull back on a finished Cynthia, Lucina pulled back her fingers and drove her tongue inside her sister, surrounding herself with the taste, the soap-and-salt taste of Cynthia combining with her husband to send her wild. Lucina felt her mind blank as the orgasm hit her, her entire taut body shaking with the pleasure of climax, the damnable buildup of their clinch finally letting go in a way that felt so, so good. And she screamed; screamed for Robin, for Cynthia, for their unlikely clinch, for the downright ridiculous way this was all kinds of messed up but oh so very good in the end.

The room filled with the sounds of heavy breathing, with three people sated -- for now at least -- in the warm, rushing afterglow of coming for a lover. Robin pulled unsteadily out of Lucina, his seed forming a catenary strand between his erection and Lucina’s cunt, before it snapped. Robin leant forward and kissed his wife between the shoulders, her pale skin flushed and hot under his lips. “Luce, I love you,” he murmured, “you made me feel so good. Both of you.” He pulled up and looked at Cynthia, panting. “Watching Luce make you come was _hot._ ”

Cynthia moaned, too spent to smirk properly, as her sister pulled her tongue back to kiss the inside of her thighs. “Oh, Lucy,” she panted, their hair a mess and both girls now a panting, twitching wreck. “Lucy, just, how are you so good at doing that,” she moaned.

Lucina smiled bashfully, her kisses butterfly-soft on the inside of her sister’s thigh, trailing a wet line up towards her knees. “Well, feel free to make it up to me, Cynthia. Robin has very definitely come inside me.” She pressed her thighs together, Robin’s seed inside her searingly warm, a testament to their mutual pleasure. She moved up and collapsed onto Cynthia’s chest, kissing the girl’s collarbone. “I might need a moment first though…”

The pegasus knight smiled, of the same mind. “Y-yeah, just-- just give me a moment too…”

Robin smiled as he saw the girls lying tired with each other. Cynthia looked at his still-hard cock and sighed. “Are you ready to go already?”

The tactician smiled, a little abashed. “Sorry. Like I said, watching you two was hot.”

“Oh, Robin, I’m a wreck, but I want you,” Cynthia moaned, as her sister kissed her neck. “So get over here and make me come again, okay?”

Lucina smiled as she felt Robin’s hands leave her and reach over her hips to touch Cynthia’s. Cynthia moaned as Robin’s erection pressed up against her wet opening.

“I meant it when I said I had more than one in me,” Robin said. He pushed into Cynthia,  relishing the hot, wet feeling of his lover around him, her tight tunnel enveloping him so pleasurably again. She felt amazing, his erection surrounded by her tightly, the pounding of his heart and the post-climax sensitivity in his nerves heightening the pleasure her warmth gave him. “We have all night, don’t we?”


	2. Chapter 2

After the fourth time, the three of them would deny that things might be getting too far. 

Chrom’s future daughters had convened in Robin’s office, ostensibly for a talk about strategy. As the former Exalt pushed open the familiar wooden door of his office to see Robin with his feet nonchalantly up on his desk, Cynthia smiling wickedly as she caught sight of her sister -- Lucina surmised that it turned out Robin had invited them there for a different kind of meeting. Cynthia winked at her sister as Robin magically engaged the lock on his chamber door from his position at the desk, the bolt sliding home as Lucina raised an eyebrow. 

“Are you worried about intrusion?” Lucina had asked, simply, only her sister’s immediate smirk signifying what might be coming imminently. It turned out, it would be the three of them. 

Lucina still had the shame to blush as the penny in her mind dropped, though in secret she was no less eager than the others to carry on with this kind of thing. “Surely you don’t mean us to sully your office, Robin,” Lucina whispered hastily, her protestation insincere, but demanded of the dutiful Exalt’s daughter. “This is not the place-- we’ll get caught, surely--”” 

“We will if you keep cursing,” Cynthia interrupted; the blue-haired pegasus rider had swooped on Lucina as Robin watched from the desk, a wry smile on his face as he watched his flustered wife. “You don’t have to pretend you hate this so much, Lucy,” Cynthia said, moving close to her sister and kissing her on the cheek. “So quit complaining and put your mouth to better use whilst I take your clothes off.” 

Lucina flushed scarlet, her face churning through expressions as she struggled to decide whether a token rebuke was worthwhile. “Fine,” she eventually sighed, unbuckling her sword belt and laying the Parallel Falchion slowly onto one of the free table surfaces. 

Cynthia smiled happily as Lucina walked back toward her, her hands wasting no time in pulling Lucina in for a kiss against the wall. The twin-tailed girl hummed appreciatively as Lucina consented to meet her lips, pulling off her tiara and pushing her tongue into Cynthia’s mouth. _If you want me to put my mouth to better use, Cynthia, I can happily oblige._  

Robin looked at the timepiece on the wall; it had been only a few minutes since they had met. “I guess I owe you, Cynthia; I was _sure_ it would take Luce longer than this to agree.”

He smiled as Lucina broke their kiss to look at him; she only looked moderately disdainful, the dismissive glare tempered by her desires exactly what he wanted to see. 

“I don’t know how we’ve arrived in a world in which I’m glad my husband is conspiring to seduce me with my sister,” Lucina lamented, Cynthia continuing to tug at her clothes, “but here we are. Robin, quit gawping and come over here.” 

The man retracted his feet, standing up and moving over to them after shrugging off his tactician’s coat and putting it aside. He watched as Cynthia wasted little time with her hands, her kiss with Lucina continuing whilst she started to take their clothes off. Lucina’s blue, gilt-edged tunic consented itself to come off quickly, slipping off-and-over Lucina’s shoulders in no time; Cynthia’s partner shivered as the girl’s hands rubbed her skin, the touch already welcome even through her navy undershirt. 

Robin moved up behind Cynthia and started pulling at her clothes, his hands running up the vents of her tunic around the thighs, the exposed triangles of her flesh shivering as he touched her, the girl moaning as he unsnapped the belts holding her thigh-high boots in place. “Has anyone ever told you how terribly your legs are flaunted by your outfit, Cynthia,” he murmured, even as his hands exposed even more of her skin. 

“I thought we were here to get rid of clothes,” Cynthia grumbled, Robin pulling off her leggings before meeting the others in their kiss. Adding his tongue to the efforts of the two girls’ quickly turned things into a sloppy, unorthodox mess; but Robin prided himself on adapting to unfamiliar strategic situations, and tried his best.  The three of them wrestled to get as much of the other two as they could; Cynthia hummed open-mouthed, as her tongue ran wetly across Robin’s, Lucina’s darting over the back of his as they enjoyed the taste and feeling of each other. 

In pretty short order, the three of them were down to their underwear, their clothes a scattered pile on the floor. Their mouths and cheeks were now covered in each other’s saliva, as their kiss had only got more disorganised. Hands were running over each other’s firm midriffs and toned butts, small gasps coming from each of them as their skin touched. Robin’s cock was pressing firmly into Cynthia’s ass, as Cynthia was pressed under him into her sister, the two girls pinned by him against the wall. Lucina and her sister moaned appreciably as their toned stomachs rubbed together under the effort. 

“I think that underwear needs to come off right now, Robin,” Cynthia panted, her sister nodding quickly in agreement. “... So long as that door is locked.” 

“It is, so let’s get rid of the rest,” Robin smiled, hands gently squeezing Cynthia’s not-insignificant bust through her lacy bra, to her vocal approval. “Here. I’m happy to oblige.” 

“Your cock felt REALLY good pressing against my ass, Robin,” Cynthia moaned, as she pulled off Lucina’s bra, the girl reciprocating for her as Robin shucked his own undergarments. His cock sprang free into the air of his office, both girls turning to look at it as Cynthia began talking. “Mmmm,” she continued, tongue running subconsciously over her full, wet lips. “I have an idea for that.” 

“I have an idea, too,” Robin replied, motioning with his hand as he made his next request. “Why don’t the two of you turn around so I can explore your naked bodies a bit?” 

The women in his life were happy to oblige, muscular backs pressing against the wall as the girls stood next to each other. Robin demonstrated his intent, moving forward and slipping his hand between each of their legs. Lucina moaned softly, covering his hand with hers and pressing him gently between her lower lips; Cynthia was louder, pressing her mouth to his neck as her own hand found his hard, throbbing erection. 

Robin hummed in pleasure as Cynthia’s hand squeezed him, and began to slowly move his own hands over each girl’s centre of pleasure. His fingers slipped slowly, enticingly over them; Robin wanted them to feel good, but there were better ways to come for each other. 

“What was your idea?” he asked Cynthia, who was panting with her shoulder on his neck. 

“I thought your cock felt good rubbing against my ass,” the twin-tail continued to moan, “but that made me think, I don’t think it’s right for you to fuck me like that before your wife gets first refusal. So, ahh, I wanna watch you fuck my sister. In the ass.” 

Lucina’s response to this idea was to moan lowly and loudly, her noise of approval truly indecent; Robin’s hand against her core had heightened her arousal, and she pressed his hand firmer into her as she imagined him in her firm ass. “ _Gods,_ ” Lucina hissed, as she contemplated her sister’s suggestion. “Yes, _please.”_  

The tactician’s cock flexed reflexively in Cynthia’s hand as her words went through his brain; the idea of taking his wife’s anal virginity whilst her sister watched maddeningly arousing. “A-Are you sure, Luce,” he moaned, as Cynthia’s hand rubbed his cock, thumb running over the top and spreading the first traces precum over his shaft. 

“Do it,” Lucina nodded, her face flushed as she pulled him into a kiss. Robin smiled as they broke apart. “How could I turn down such an invitation?” 

Without any more words, Robin guided his wife between himself and Cynthia, and began kissing his way down her back to tease her ass with his tongue. Lucina gasped as he made contact with her butt, his fingers spreading the cheeks of her ass apart as he began to deliver a truly lewd series of kisses. Lucina took the opportunity to lean into her sister’s chest, kissing the way down the girl’s flushed skin to a position where she could do something about Cynthia’s huge, soft breasts, now free to the air. The princess took them in her hands and squeezed them firmly, Cynthia moaning full-voiced at the feeling before her approval turned to a near yelp, as her sister began to tend to her nipples with her mouth. The twin-tail’s noises were lewd as Lucina’s lips and tongue covered first one and then the other breast with hot licks and hard sucks, both girls’ knees trembling as they felt warm breath on wet skin in different places. 

“Please, Lucy, keep going,” Cynthia urged, the girl pressing her thighs together involuntarily as her fingers had replaced Robin’s, seeking a continuation of her pleasure. Lucina dutifully continued to tease Cynthia’s hardened nipples with her teeth now. Cynthia’s approval rang fitfully around Robin’s office each time Lucina grazed her softly. The sharp pleasure in her breasts was hot, and it travelled straight through Cynthia to her rapidly wetter pubic mound. It was already too much, and as she watched Lucina’s eyelids fluttering in tandem with Robin’s tongue, the twin-tail gave in, howling as she came around her fingers. 

The former Exalt pulled back in surprise, unsure whether to look pleased or surprised; Cynthia pulled her into a messy kiss, newly-free hands sneaking around Lucina’s waist to hold her ass open for Robin. 

“Thanks, sis,” Cynthia said, after a few moments of come-down, Lucina squirming as Robin licked her ass. “I’m not gonna watch.” She kissed Lucy on the cheek. “Let me lick you whilst he does,” she whispered, before dropping to her knees against the wall, pulling her sister forwards and guiding the girl’s sodden entrance into her mouth. Lucina shuddered as she felt her sister’s intentions become action, the double assault unlike anything she could think of. Her hands sought purchase against the wall, and she wrapped her fingers into Cynthia’s hair, simultaneously pulling the girl’s mouth in harder and stopping herself from falling over. 

“Robin, please, I need you inside me,” Lucina begged. 

Her husband delived a final kiss to her ass, and stood behind her, his precum slicked member rubbing against it to confirm he’d done a good job. Robin slid two fingers into his wife’s mouth, causing Lucina to moan as she felt them hit her tongue, the bright flavour of Cynthia from a few moments ago flooding her mouth. “I’m going to fuck you in the ass, and you’re going to cum inside your sister’s mouth, understood?”

 More noises of approval came from Lucina as Robin pushed his fingers further into her mouth, muffling her voice. He could feel her tongue desperately wrapping round them, sucking at the taste of her sister. After a few moments, Robin pulled them back and began rubbing Lucina’s spit-soaked anus, the thick saliva from her mouth and his allowing him to effortlessly lube her up. His wife moaned as she felt him push a finger easily inside her, Robin’s index finger slipping in up to the knuckle quickly before a second began to probe for entry. “ _Gods,_ that has no right feeling this good,” Lucina gasped, as Robin’s fingers spread her open, Cynthia’s mouth sucking gently on her clit. “Robin, please, no more teasing,” she begged, trying to firm up her legs as she felt him in her ass. “Please, get your cock in my ass _right fucking now_.” 

The tactician was only too happy to oblige, Cynthia’s hands continuing to hold Lucina’s butt wide as Robin pulled at her hips, hilting his cock within her ass within moments. “Ahhh,” Lucina cried, as Robin let out a held breath, the tightness of her back tunnel overwhelming  for both of them. “Gods, Luce,” he moaned, “you’re so tight back here.” 

“How do you two make me abandon all reason like this--” Lucina was near-crying in pleasure, half-conscious as her sole focus was the way both of them felt inside her. It felt amazing, the sheer taboo of this improbable act driving her to a ridiculous height of lust. She could think of nothing except her sister’s tongue and Robin’s hard dick in her ass, the way they were spreading her open and making her wet, the sounds of them working on her in tandem intensely arousing. 

“Your husband is fucking your ass in public, Lucy,” Cynthia chided, between kisses to her sister’s clit. “At least have the decency to cum in your sister’s mouth.” 

Lucina’s body began to twitch, her cunt and her anus squeezing desperately at their respective invaders, the pleasure building in each. “Ahh, auuhhh,” Lucina cried, as she felt her climax beginning to build, “I-I’m so cloose, it feels s-so good--” 

“Well, if you need something dirtier to think about, Cynthia can always lick the cum out of your ass once I’m finished with you,” Robin whispered in her ear as his fingers dug into her waist. “I don’t think one load will be enough, though. I might have to fuck you back here again and again.” 

His wife groaned desperately, her anus clamping down around him at his pillow-talk, the slickness of his precum meaning he could still continue to thrust into her ass easily. “Ahhh,” she panted, pulling at Cynthia’s hair as the girl licked her, faster now. “A-are you c-close too, Robin?” 

“Yeah,” Robin breathed curtly, unable to talk much more, his own orgasm imminent. “L-Luce-- Cynthi-aaah--” 

“C-cum for me,” Lucina urged, her exhortation finally enough for Robin to find his release. The experience of claiming her ass for the first time had been overwhelming. He hilted his cock inside her ass as she tipped him over the edge, his cum flooding her ass as it pulsed from his cock in strong spurts. Lucina whimpered as she felt his hot semen invading her, the sensation filling her ass warmly; it felt heavenly, Robin’s desire for her and pleasure in her manifest, and Lucina’s eyes rolled back as she reached her own climax too. 

Her hips shook as she came hard, gyrating erratically between Robin’s cock and Cynthia’s tongue, the dual sensation between her cum-filled ass and the tongue on her cunt causing her to cum in long, loud cries. Her sister made noises of approval as she felt Lucy tighten around her fingers, and she licked Lucy’s core enthusiastically as her sister came, prolonging the pleasure with quick movements of her tongue. 

When Lucina’s unstifled moans had broken off, replaced with a hot, desperate panting, and Robin had done the same, Cynthia pulled back and kissed her sister’s stomach, pulling her fingers slowly out from deep inside of her. “Was that good?” she asked Lucy enthusiastically, the other girl too exhausted to do much more than nod gratefully.

 “Y-Yeah,” Lucina panted, “hah, good, haah, good heavens, Cynthia, R-Robin…” 

Her husband felt pretty much the same way, and Robin could do little more than kiss Lucina’s neck as he panted for breath, Cynthia standing up and taking them both in her arms. “That was so hot,” Cynthia grinned. She leaned in to whisper in Lucina’s ear. “I think Robin had the right idea, Lucy. Turn around so I can clean you up.” 

Spent as she was, Lucina moaned as Cynthia’s hands guided her around, the twin-tail dropping to her knees again to follow through on the idea. Lucina’s forehead hit Robin’s neck as she felt the wide, broad strokes of the other girl’s tongue, running across Lucy’s cum-stained ass and tasting the mixture of them. Cynthia moaned and her hand slipped back between her legs, the taste highly arousing.  “Come here, Robin,” she gestured, opening her mouth and taking his cock into it, her tongue eagerly flooding around his erection to be rewarded with that same mix of tastes. 

Lucina moaned quietly as she watched her sister clean the taste of her ass from her husband’s cock, the knight moaning in lewd, self-satisfied noises as she sucked greedily on Robin’s member. Robin himself had his eyes screwed up in overstimulation as the girl cleaned him up. 

“Itsh sho good,” Cynthia moaned messily, Robin’s member now covered in her saliva, her tongue having roamed over him freely and covering him in a thick layer. She pulled back slowly, kissing the tip of his cock as she inspected her handiwork. “Think you can fuck her in the ass again?” 

Robin moaned and his cock twitched in Cynthia’s warm grip, the girl taking him back into her mouth and smiling as he thought it over. He looked desperately at his wife, his face red and flushed with the pleasure, Lucina shivering as she saw the desire in his eyes. _It probably matches mine._ She leaned in and kissed him slowly. 

“Again, Robin,” Lucina urged, leaning forwards against the wall herself this time, her own hands reaching behind her to spread her taut butt open, her ass still slick from Cynthia’s clean up. Her sister moaned as she pulled Robin from her throat, kissing the tip of his cock again. “Mmm,” Cynthia smiled, as she looked up at the man, “we shouldn’t disappoint my sister, huh.” She pulled Robin by the cock forward, lining him up with her sister’s ass, the sensation of two wet, stimulated arousals rubbing together causing them both to moan. “Easy now,” Cynthia whispered, and her fingers pushed further into herself as she watched Robin once again claim Lucina’s ass. 

“Auhhh,” Lucina drooled, struggling to speak as she could think of nothing but the hot sensation of her husband filling her wet, stimulated ass. “D-don’t you n-need a turn, Cynthia?” 

“There’s no rush,” Cynthia replied, her grin still wicked, enjoying the sight of her usually-stiff sister melting in front of her. “Robin’s a big boy. I can have him when your ass can’t hold any more of his cum.” 

The princess groaned, Robin’s hands fingering her clit as he pounded her ass. Her body responded, squeezing her anal passage tight around him as he kept thrusting, his cock pushing forward to spread her open under him. The sensation was incredible, the tight ring of her anus being spread by his hard, firm cock, Cynthia’s clean-up act lubricating them both even more and causing their nerves to dance as they both chased a second orgasm.

 “Gods, Robin, it’s even better this time,” Lucina cried, any shame at this shameful pairing long-since chased out by the direct feeling of pleasure as he claimed her ass; and then she felt Cynthia’s tongue hit her cunt again and she could think of nothing but pushing the girl’s mouth in more firmly. Cynthia moaned at the sodden, aroused taste of her, Lucina filling her mouth messily as Cynthia pushed her tongue as deep into her as she could manage. The three of them were drunk with each other, all semblance of normality gone, Cynthia’s ridiculous enabling driving them wild, even as the girl seemed content to play enabler rather than take her own turn.

 Robin moaned as his wife’s ass gripped his cock, the warm, tight sensation incredible, the urge building to let everything he had go inside her rear. “Luce, I’m gonna cum again _already,”_ he whimpered, feeling the tell-tale ache in his cock as the climax began to build.

 “Do it,” Lucina whispered, her voice as sultry as she felt, “Like my sister said, you need to do it as much as you can. Go ahead and cum in my ass, Robin, and then I want you to do it again, until neither of us can _stand_.” 

Cynthia moaned into her sister. “Yesss,” the pegasus knight moaned, kissing Lucy’s clit gently between words, her sister near-writhing. “And I’ll keep cleaning you up, and making you cum as much as you can. So long as you both can manage, that is.” Her eyes sparkled. “Should we bet on how many hours  _that_ will take, Robin?” 

“Maybe, nnnnf--” Robin’s eyes rolled into the back of his head as his head hit Lucina’s shoulder and the sensation of her tight, Cynthia-approved ass made his cock explode in her again. Lucina screamed as she felt him pulse violently inside her tight ass, so full of his cum already she could feel it leaking from her before he had finished sending yet more in. 

She came again in her sister’s mouth seconds later.

* * *

  The room was dusk before they had finished.

 “Oh, Robin, it _hurts_ , but in a good way,” Lucina sighed, her limbs unsteady, standing impossible; the woman was spreadeagled on the floor, Cynthia beside her as it was her turn to recover now, the hours of buildup causing Cynthia to nearly pass out by the time she had cum with Robin fucking her ass.

 “How many times did he cum in your ass, Lucy, five, six?”

 “Six,” Robin groaned, a dull ache in his cock. Seven, if you counted Cynthia’s too; and he still didn’t think they were done.

 Cynthia kissed her sister’s neck blankly as she panted for breath,  Lucina running her hands gently up and down the girl’s sides. “Six,” Cynthia smiled weakly, “I’ll forgive you if you can’t match that with me."

 “We won’t know if we don’t try,” Lucina said, kissing her sister on the cheek. “You don’t have to stand up this time. Why don’t you lie on top of me instead?”

 

**Notes for the Chapter:**

> This has been a ride, huh?
> 
> I've been wanting to write some FE smut for a while now. This is a bit more adventurous than what I'd usually go for. Hopefully you enjoyed it.  
> I liked the ship, though, and Cynthia is criminally under-represented. I consider her a lot like Severa or Morgan; a big mouth and a horribly enabling attitude.  
> I'm sure you'll see more FE stuff from me soon... :)


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